Extubation refers to removal of the endotracheal tube (ETT). It is the final step in liberating a patient from mechanical ventilation. Issues that need to be considered prior to extubation, the extubation procedure itself, and management after extubation are described here. Outcomes following extubation are also discussed. Predictors of weaning success and methods of weaning from mechanical ventilation are reviewed separately. (See "Weaning from mechanical ventilation: Readiness testing" and "Methods of weaning from mechanical ventilation".)
PRIOR TO EXTUBATION
At the end of the weaning process, it may be apparent that a patient no longer requires mechanical ventilation to maintain sufficient ventilation and oxygenation. However, extubation should not be ordered until it has been determined that the patient is able to protect the airway and the airway is patent.
Airway protection — Airway protection is the ability to guard against aspiration during spontaneous breathing. It requires sufficient cough strength and an adequate level of consciousness, each of which should be assessed prior to extubation. The amount of secretions should also be considered prior to extubation because airway protection is significantly more difficult when secretions are increased.
The importance of cough strength and the amount of secretions was illustrated by two observational studies that showed that successful extubation directly correlated with strength of the spontaneous cough and inversely correlated with the frequency of suctioning [1,2]. These studies were limited by their use of semiobjective measures of cough strength and secretion amount. Several subsequent studies addressed this limitation:
- An observational study of 130 patients who had passed a spontaneous breathing trial demonstrated that extubation failure was more likely among patients who were unable to cough on command or who had a peak expiratory flow rate during a cough of <35 L/min (24 versus 3.5 percent, relative risk 6.9, 95% CI 2.0-24) .
- Another observational study enrolled 88 patients who had passed a spontaneous breathing trial and were being considered for extubation . Extubation failure occurred in 14 patients (16 percent). Patients were more likely to fail extubation if their peak expiratory flow during a cough was ≤60 L/min (relative risk 4.8, 95% CI 1.4-16.2) or their secretions were >2.5 mL/hour (relative risk 3.0, 95% CI 1.0-8.8). The study was limited by its small sample size, leading to imprecise estimates of the magnitude of effect.